A numerically controlled machine tool is generally provided with plural axes and plural driving shafts such as spindles, feeder shafts or the like. Such a numerically controlled machine tool as is provided with plural axes generally requires a large scale numerical control equipment having plural control elements. Since such large scale numerical control equipment is complicated in structure.
This invention employs plural small scale numerical control equipment, which is simple in structure, in parallel to each other, in order to control the foregoing numerically controlled machine tool having plural axes.
This idea can be applied to machining wherein relative motion is required between different spindles, between one or more spindles and one or more feeder shafts, and/or, between different feeder shafts. To achieve this, each control equipments for driving shafts and each negative feedback circuits which feeds back signals representing the angular position (hereinafter referred to as angular position signals) of the shafts to the control equipments is required to be connected with the numerical control equipment which controls another axis that must rotate to keep the foregoing relative motion. However, a numerically controlled machine tool that can be connected to for driving a shaft and that including a negative feedback circuit which feeds back the angular position signal of the driving shaft to the control equipment and that includes a means for connecting relevant negative feedback circuit with the numerical control equipment which controls another axis which is required to rotate so as to maintain relative motion with the driving shaft, is not presently available.